Building panels of various kinds have been constructed over the years with innumerable external facings and innumerable insulating materials associated therewith. However, they all have drawbacks which make them more or less desirable under diverse circumstances.
It has been customary in various phases of the industry to construct building panels with a cavity between two surfaces and fill the cavity with insulating material such as fiberglass rockwool. But the problem with the cavity concept is that the insulation tends to compact over time and settle to the bottom of the cavity, thereby creating a tremendous heat transfer coefficient differential between the top and the bottom of the wall.
Pressed insulation board in combination with poured concrete is another conventional type of wall panel used. Ordinarily, this type of structure is a prefabricated panel where the fiberboard is disposed either on the top or bottom of a concrete slab with tie bars extending through both elements before the concrete hardens. One problem with this structure is the control of the heat transfer coefficient by moving the wall surface inward as the insulation thickness is increased; thereby reducing the internal dimensions of the rooms of the structure.
A third common panel construction includes filling the cavity between the external sheathing and the internal drywall with a foamed resin. Usually the resin is injected after the wall panel is erected. In this case, the heat transfer coefficient is controlled by the foam density and its thickness. The thickness in turn is controlled by the standard thicknesses of the support elements within the wall. Accordingly, the building resident cannot specifically control the heat transfer coefficient; he can only change in from one fixed value to another.